1. Field of the Invention
This invention relates to a resectoscope device to be inserted into a bladder through a urethra to scrape and resect the endogland of a prostate swollen by a prostate swelling disease or the like off the exogland.
2. Related Art Statement
Recently there is extensively used an endoscope which can be inserted in the insertion part into a body cavity to observe, diagnose and cure an affected part or the like. In such an endoscope, there is a resectoscope device formed to be inserted into a bladder through a urethra so that a prostate can be resected or operated on by passing a high frequency current through a resecting electrode means.
Generally, a resectoscope device comprises a hollow resectosheath to be inserted through a urethra, a handle part having a slider removably fitted to the rear end side of the resectosheath and an observing scope removably fitted from the rear end side of the handle part and has an electrode means forked and looped at the tip to resect a prostate so as to be inserted through the above mentioned resectosheath and to be fixed at the rear end to the slider so that the resecting part at the tip of the electrode means may be projected out of and retracted into the tip of the resectosheath.
Now, in the conventional resectoscope, the positional relation of the inside surface of the sheath with the electrode means, scope and handle is not kept constant. Therefore, the insertion part of the handle, in which the scope and electrode means are inserted and combined within the sheath, will not be parallel with the axial direction of the sheath but will be inclined, the visual field of the scope in the tip part of the sheath will be eclipsed, the entire operation field will not be able to be fully observed and the operation will be obstructed from being safely and efficiently made. There has been also a problem that, due to the above mentioned inclination, the resecting part at the tip of the electrode means may catch on a beak opening at the tip of the sheath so as to be immovable or may be broken.
In order to solve the above mentioned problems, the visual field angle is narrowed to prevent the visual field from being eclipsed or the dimension of the resecting part is made small to prevent being caught on the beak opening. However, thereby, the efficiency of the operation will be reduced and the operating time will become longer. Thus, it is not an effective solution.
U.S. Pat. No. 4,134,406 discloses a cylindrical stabilizer for inserting a scope in the axial direction provided on the way of an elongated electrode means inserted within a sheath. However, this prior art example is effective to guide the scope so as to parallel with the axial direction of the electrode means but can not make the scope parallel with the axial direction of the inside surface of the sheath.
In U.S. Pat. No. 3,939,839, it is disclosed that a metal leg of a fixed height for holding the handle in a fixed position with respect to the inside surface of the sheath is provided below the insertion part of the handle with a view to making the joint of the sheath body with the handle water-tight. However, in this prior art example, when the positional relation between the inside surface of the sheath and the handle is directly determined, the above described problem with the insertion part of the handle, in which the scope and electrode means are inserted and combined, inclines with respect to the axial direction of the inside surface of the sheath, can be effectively prevented. However, the handle is to be used in common with sheathes of various thicknesses. If the thickness of the sheath is different, the positional relation between the insertion part of the handle and the inside surface of the sheath will naturally vary. Therefore the sheath of the thickness of the inside diameter, in which the tip of the above mentioned metal leg just contacts the inside surface of the sheath will work but, with the sheath of an inside diameter thicker than that, the same problem as is described above will occur.
Further, in the resectoscope device disclosed in U.S. Pat. No. 4,060,086, the forked part on the tip side of the shaft part of the electrode is inclined to the upper side so that the looped resecting part at the tip of the electrode means will not catch on the beak opening when the handle is operated. However this electrode means is fixed only on the handle side, is likely to be influenced by the slightest backlash or the like on the handle side and is difficult to actually set or hold in this state. Even if the electrode means is set in a proper inclined state, in case it is pressed against an affected part to be resected, it will be deformed and, when it is disassembled after being used, it will be likely to be varied from the proper inclined state by the operation and will have to be readjusted.